The purpose of this research was to investigate whether interactivity yields a learning effect when used appropriately in e-Learning Systems, and whether this effect enhances learning. The importance of interactivity for success in learning has always been paramount; however, little scientific evidence can be found to support this importance (Sims, 2003; Leiner & Quiring, 2008). Thus, this research aims to provide evidence of the impact of interactivity on e-Learning Systems considering three main agents: the learner, the teacher and the system (educational triangle). A key element often found to be related to learning and the three previously-mentioned agents is the concept of feedback. The use of interactivity as part of a feedback mechanism for enhancing learning is well documented in this research. Three empirical studies were designed to investigate interactivity within the educational triangle. These three studies, developed to support the research hypotheses, were conducted based on the framework of positivism and action research paradigms. The first study, entitled “Interactive Pedagogical Feedback”, aimed to gather evidence for how highly interactive pedagogically-designed formative feedback enhances students’ memory and understanding. The two student groups to which the interactive conditions were added showed a significant difference in the post test scores. A one-way ANOVA with a Turkey HSD post hoc test for all pair wise comparisons reveals a significant difference between the transfer and no condition scenario. The second study, entitled “Interactive Audio Feedback”, examined whether the speed enhancements of oral feedback improve the conditions for the production of lecture’s feedback and the quality of the feedback delivered to the students. The use of the interactive condition reduces by 40 to 65% the time it usually takes to prepare feedback for final assignments, and an unpaired Student’s t-test shows significant differences in the use of the two conditions. The final study, “Interactive Texting Feedback”, took a pedagogical approach to provide formative feedback to a student audience using mobile text messages. It aimed to determine whether Interactive Texting Feedback enhances the leaning experience within the e-Learning environment. Inferential analysis demonstrated good correlations in the use and benefits obtained by the introduction of the interactive mechanism. The results indicated that interactivity is critical in promoting and enhancing effective learning. Learning theories led by the generative theory of learning (Wittrock, 1974) and the principles of multimedia learning (Mayer, 2001) provide scientific explanation for this findings.